Investigation of hot extruded GW84 alloy on high temperature tensile properties and microstructure evolution

The tensile properties and microstructure of hot extruded GW84 alloy stretching at 200 degrees C, 250 degrees C and 300 degrees C were investigated. The results showed that the alloys had excellent high temperature mechanical properties, when stretching at 250 degrees C, the ultimate tensile strength of alloy reached peak value, 393 MPa, and the tensile strength stretching at 300 degrees C reached 354 MPa. During high temperature tensile process, the microstructure markedly changed, which is not recognised in previous researches. Stretching at 200 degrees C, the precipitate phase was still metastable beta' phase. However, when stretching at 250 degrees C, the nano beta' precipitate transformed into nano beta phase (beta' -> beta), and the precipitation mechanism is mainly inoculation nucleation of beta phase. When stretching at 300 degrees C, the number of beta precipitates increased significantly at triangular grain boundaries, which grew up to submicron particles, and precipitation mechanism is mainly growth and coarsening. (C) 2021 The Author(s). Published by Elsevier B.V.